1. Field of the Invention:
This invention relates to a method and apparatus for closing one end of a shirred synthetic casing stick as well as to a shirred synthetic casing stick closed at one end.
2. Description of the Prior Art:
Tubular synthetic casings for stuffing meat emulsions such as highly seasoned minced meat, particularly sausage casings made of regenerated cellulose, are generally thin-walled long tubular bodies. These tubular casings are used in the form of shirred cylindrical bodies, in other words, as shirred casing sticks with a stuffing machine for a meat emulsion such as a highly seasoned minced meat.
Early types of shirring machines and shirred casing sticks are disclosed, for example, in Japanese Pat. No. 274,407 (Japanese Pat. Publication No. 15,792/1960 publsihed Oct. 20, 1960), Japanese Pat. No. 277,857 (Japanese Pat. Publication No. 17,582/1960 published Nov. 30, 1960), Japanese Pat. No. 310,260 (Japanese Pat. Publication No. 2,131/1963 published Mar. 14, 1963), U.S. Pat. No. 2,722,714 issued Nov. 8, 1955 to James R. Blizzard et al., and U.S. Pat. No. 3,454,982 issued July 15, 1969 to Lionel C. Arnold.
In actual practice the casing stick used on a stuffing machine is obtained by shirring a casing of 20-30 .mu.m in wall thickness and 12-50 m in length to a length 1/30-1/120 of the initial length by means of a shirring machine.
After producing shirred casing sticks (hereinafter referred to as "sticks" for simplicity), they are packed and shipped to meat processors, where they are used with meat stuffing machines.
Manual or automatic stuffing machines are used for stuffing. An example of automatic stuffing machines is disclosed in Japanese Pat. Publication No. 5,899/1966 published Mar. 30, 1966, in which each stick is automatically mounted on a stuffing pipe, filled with a meat emulsion and finally formed into links of a uniform length.
To permit a stick to be stuffed by means fo such an automatic stuffing machine, it is necessary that one end of the stick be firmly closed. Otherwise, it is impossible to extend the pleats of the stick by the internal pressure of the meat emulsion stuffed into the stick under pressure by a stuffing machine. In addition, if one end is not closed the meat emulsion will inevitably be scattered around upon filling. Thus, meat processors will suffer from lost productivity, wasting of meat emulsion, etc. and certain sanitary problems will arise. Also the closed end portion of a stick should be made of the same material as the stick per se because it is necessary to recover the meat emulsion stuffed into the closed end portion.
Examples of sticks closed at one end and methods for closing one end of a stick are disclosed in the following Japanese Pat. Nos. 534,004 (Japanese Pat. Publication No. 13,663/1968 published June 10, 1968); 540,883 (Japanese Pat. Publication No. 24,936/1968 published Oct. 28, 1968); 719,815 (Japanese Pat. Publication No. 25,119/1973 published July 26, 1973); and 755,165 (Japanese Pat. Publication No. 4,953 published Feb. 4, 1974).
However, such conventional sticks have drawbacks in that their safety is not sufficient or casing materials are wasted.